Here I go again...

I have a nice (for me) Gundlach Rapid Rectigraph 12/21/28 f/8 convertable that I would love to use. Unfortunately, it's in a Universal dial-set shutter. The one shutter Steve Grimes stated was a "dog" and not worth repairing... I agree with him. Every speed from 1/10 up is the same, and the slower speeds are half what they should be...

The second problem is that I really don't consider this lens worth the investment of a new shutter and mounting. It would cost more than a replacment lens of similar design.
Now for a slight ray fo hope. I finally managed to un-stick the lens element to shutter adapter ring and unscrew it. Then I started checking my other lenses for a compatible shutter. First one I pulled out was my 10" Ektar in an Ilex No.4 Acme Synchro. It's a perfect fit! (Can't check the rear threads yet cause I can't get that ring unstuck so far...)I should be happy... Until the question came up...

How standard are shutter threads? If I happen to find a lonely Acme #4 that I could afford, what's the chances of it having the same threads? I'm kinda hoping that they all have the same threads and use the adapter rings to mount the lenses, as my Ektar has in the Acme and Gundlach in the Universal. And anyone know of another shutter with the same size threads? I haven't seen too many Acme #4's around...
As usual, thanks

The closer you get to today, the better the interchangeablility.

I can't say with any authority, but I would suspect that MOST Acme No 4s use the same thread. Since these were from the 50s to the 70s.


I found out the hard way that Compound shutters differ in their permanently mounted extension tubes. Some shutters are flat, some have tubes. I picked the wrong shutter to have Steve Grimes set up for a pair of Protar lenses, and now that I have a second pair the new pair won't fit. Had I found a flat shutter to start with, things would have been fine.

Thanks Les. I'll start keeping an eye open for a #4 but it may take a while to find one. I have more hopes of trying to find a bad/broken lens mounted in one going for cheap...
So the tubes in Compounds are permanent? That's good to know. I may be having trouble getting them out of this Universal, but at least I know they're supposed to unscrew.
The problem with the rear tube is that someone glued the shutter into a C board. Of course the glue & board just reach the threads on the tube... I may start trying solvents soon.... And I won't know for sure that I can use that #4 until I get the rear tube out. But if I do, I suppose I could treat the whole thing like a convertable. Just unscrew the lens & tube for the switch. The f-stop scale is another matter though. A temporary solution at least...
So the fun continues